This invention relates to a device for in situ producing and building up of a fibre-reinforced construction material, particularly a mortar or a plastic.
It is well known that by incorporating fibres into e.g. lime mortar and cement mortar, the strength of the mortar after setting is substantially increased. Any kind of fibres will have this effect, but inorganic fibres are preferred, such as asbestos fibres, mineral wool and glass wool, especially in the form of glass wool made from alkaliresistant glass.
The reinforced mortars have many uses, such as in the production of light partitions, and of kerbstones, or to make fire-inhibiting coatings on supporting structures, as well as in the production of substitute materials for wood in the building trade, especially for making window frames and door frames for use in the manufacture of prefabricated building units.
In order to reduce manufacturing costs, several attempts have been made to produce the fibre-reinforced mortar mixture in situ. In the most successful attempt of this kind, an air-born stream of glass fibres is produced by feeding glass wool in rowings to a cutter and blowing the cut fibres out through a tube by means of pressurized air. At the end of the tube two oppositely mounted, inclined nozzles are mounted to spray a low-viscous mortar into the air-born stream of glass fibres to produce a mixture of mortar and fibres immediately before depositing the mixture at the site of use.
By this method, however, it is difficult to avoid severe losses of both fibres and mortar, since the intermixing depends on the mortar splashes hitting and attaching themselves to the individual tufts of fibres produced by the cutter. Also, the fibres settle at random on the surface, to which the mixture is applied, with the result that extensive after-treatment is required to orient the fibres parallel to the surface and to remove possibly enclosed air bubbles.
Since this after-treatment has to be carried out manually by applying rollers to the surface of the coating, any improvement in respect of making the fibres in the mixture settle parallel to the surface of the coated object will mean a saving in costs.
Fibres are also used for reinforcing fillerized plastics of the kind being cured by addition of a hardening agent, e.g. plastics of the epoxy or polyester type.
Although such fibre-reinforced plastics are increasingly used in constructional work, ranging from boat hulls to bathing cabinets, apparently it has not hitherto been possible to provide a device by which a mixture of fibres and heavily fillerized plastics can be produced in situ.